On Fri, Dec 17, 2010 at 2:31 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> Another possibly-useful thing about mandating a full page header for >> every page is that it might give us a way of avoiding unnecessary full >> page writes. As I wrote previously: > > Could we do that via a bufmgr status bit, instead? Heikki's idea has > the merit that it actually reduces bufmgr's knowledge of page headers, > rather than increasing it (since a buffer marked UNLOGGED would need > no assumptions at all about its content).
That was my first thought, but it doesn't work. The buffer could be evicted from shared_buffers and read back in. If a checkpoint intervenes meanwhile, we're OK, but otherwise you fail to emit an otherwise-needed FPI. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
